Aerosol Generating Device

ABSTRACT

A system includes an aerosol generating device and a portion of aerosol generating substrate, the device including first and second housing elements configured to move between open and closed positions, wherein, in the closed position, the housing elements together define an aerosol generation chamber configured to enclose the portion, and further define an air flow channel including an inlet, an outlet and the chamber, the first housing element including a recess for receiving the portion, wherein the recess includes a flat bottom surface, and the second housing element includes a compression surface for compressing the portion towards the bottom surface, the compression and bottom surfaces being opposing surfaces of the chamber, wherein the portion is cuboid and a thickness of the portion before use in the device is greater than a distance between the compression and bottom surfaces when the first and second housing elements are in the closed position.

TECHNICAL FIELD

The present disclosure relates to an aerosol generation device in which an aerosol generating substrate is heated to form an aerosol. The disclosure is particularly applicable to a portable aerosol generation device, which may be self-contained and low temperature. Such devices may heat, rather than burn, tobacco or other suitable aerosol substrate materials by conduction, convection, and/or radiation, to generate an aerosol for inhalation.

BACKGROUND

The popularity and use of reduced-risk or modified-risk devices (also known as vaporisers) has grown rapidly in the past few years as an aid to assist habitual smokers wishing to quit smoking traditional tobacco products such as cigarettes, cigars, cigarillos, and rolling tobacco. Various devices and systems are available that heat or warm aerosolisable substances as opposed to burning tobacco in conventional tobacco products.

A commonly available reduced-risk or modified-risk device is the heated substrate aerosol generation device or heat-not-burn device. Devices of this type generate an aerosol or vapour by heating an aerosol substrate that typically comprises moist leaf tobacco or other suitable aerosolisable material to a temperature typically in the range 150° C. to 350° C. Heating an aerosol substrate, but not combusting or burning it, releases an aerosol that comprises the components sought by the user but not the toxic and carcinogenic by-products of combustion and burning. Furthermore, the aerosol produced by heating the tobacco or other aerosolisable material does not typically comprise the burnt or bitter taste resulting from combustion and burning that can be unpleasant for the user and so the substrate does not therefore require the sugars and other additives that are typically added to such materials to make the smoke and/or vapour more palatable for the user.

In such devices, a user must wait for an initial activation time while the aerosolisable material is heated to generate the aerosol, before it is possible to inhale a puff of aerosol. In order to improve user convenience it is desirable to decrease the initial activation time.

Additionally, it is desirable to increase the aerosol yield from aerosolisable material.

SUMMARY

According to a first aspect, the present disclosure provides an aerosol generating device comprising first and second housing elements configured to move between an open position and a closed position, wherein, in the closed position, the first and second housing elements together define an aerosol generation chamber configured to enclose a portion of aerosol generating substrate, and further define an air flow channel comprising an inlet, an outlet and the aerosol generation chamber, the first housing element comprising a recess for receiving the portion of aerosol generating substrate, wherein the recess comprises a flat bottom surface, and the second housing element comprising a compression surface for compressing the portion of aerosol generating substrate towards the bottom surface of the recess, the compression surface and bottom surface being opposing surfaces of the aerosol generation chamber.

By compressing the aerosol generating substrate towards the bottom surface of the recess, the thermal conductivity of the substrate can be improved, thereby decreasing the initial activation time. Furthermore, compressing the aerosol generating substrate can improve aerosol yield for a given quantity of substrate.

Optionally, the first and second housing members are connected by a hinge.

By connecting the housing members by a hinge, the housing members can be easily separated to access the aerosol generation chamber and insert and remove the aerosol generating substrate before and after aerosol generation. Furthermore, a hinge guides the housing members to compress the portion of aerosol generating substrate between the compression surface and the bottom surface of the recess.

Optionally, the device comprises a fastener for holding the first and second housing elements in the closed position.

By providing a fastener, it is not necessary for the user to apply a compression force throughout aerosol generation, making the device easier to use.

Optionally, the device comprises a gasket configured to, in the closed position, seal the air flow channel.

By sealing the air flow channel, air flows more efficiently from the outlet to the inlet through the aerosol generation chamber, and aerosol can be inhaled from the device more easily.

Optionally, the device comprises a heating element arranged to supply heat to the aerosol generation chamber through the bottom surface or the compression surface.

A heating element provides a convenient way of heating the aerosol generating substrate in the aerosol generation chamber. In alternatives, the substrate can be heated in other ways, for example, using a disposable heat source provided in the portion of aerosol generating substrate.

Optionally, the first housing element and/or the second housing element comprises an insulating member at least partly enclosing the aerosol generation chamber.

The insulating member improves efficiency of heating the aerosol generating substrate in the aerosol generation chamber.

Optionally, the second housing element additionally comprises an air flow channel configured to connect to the aerosol generation chamber in the closed position, and to provide the inlet and outlet.

Optionally, the air flow channel comprises a groove in a surface of the second housing element. A surface groove may be easily cleaned.

Optionally, the air flow channel comprises a groove in the compression surface. This increases air flow adjacent to where the compression surface compresses the substrate and improves aerosol extraction from the substrate.

Optionally, the air flow channel comprises a plurality of grooves in the compression surface connected between the inlet and the outlet.

Optionally, the inlet comprises a plurality of distinct inlets connected to the plurality of grooves.

Optionally, the plurality of grooves are arranged in parallel between the inlet and the outlet.

Optionally, a plurality of sections of the compression surface are separated by the one or more grooves of the air flow channel, and each of the plurality of sections of the compression surface is configured to compress the portion of aerosol generating substrate towards the bottom surface of the recess. This distributes air flow and compression across the substrate.

Optionally, the device comprises an electrical power source, wherein the aerosol generating device is a portable handheld device.

According to a second aspect, the present disclosure provides a system comprising an aerosol generating device according to any preceding claim and a portion of aerosol generating substrate, wherein a thickness of the portion before use in the aerosol generating device is greater than a distance between the compression surface and the bottom surface of the recess when the first and second housing elements are in the closed position.

According to a third aspect, the present disclosure provides a kit comprising an aerosol generating device according to any preceding claim and a portion of aerosol generating substrate, wherein a thickness of the portion before use in the aerosol generating device is greater than a distance between the compression surface and the bottom surface of the recess when the first and second housing elements are in the closed position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B and 1C are schematic cross-sections of an aerosol generating device, with lines x, y and z showing the relative planes of the cross-sections;

FIGS. 2A and 2B are schematic perspective illustrations of alternative portions of aerosol generating substrate;

FIGS. 3A and 3B are schematic illustrations of compression of the aerosol generating substrate;

FIGS. 4A to 4E are schematic cross-sections of different aerosol generating devices having alternative or optional features;

FIGS. 5A to 5D are schematic cross-sections of different aerosol generating devices having alternative or optional features;

FIGS. 6A to 6D are schematic cross-sections of different aerosol generating devices having alternative or optional features;

FIG. 7 is a perspective view of a first specific example of an aerosol generating device in an open position;

FIG. 8 is a perspective view of the first specific example in a closed position.

DETAILED DESCRIPTION

FIGS. 1A, 1B and 1C are schematic cross-sections of an aerosol generating device 1, with lines x, y and z showing the relative planes of the cross-sections.

The aerosol generating device 1 comprises a first housing element 11 and a second housing element 12. When the aerosol generating device 1 is in a closed position as shown in FIGS. 1B and 1C, the first housing element 11 and the second housing element 12 together define an aerosol generation chamber 13 in which a portion 2 of aerosol generating substrate aerosol is enclosed, and aerosol is generated from the portion 2 of aerosol generating substrate.

The first housing element 11 comprises a recess 131 for receiving the portion 2 of aerosol generating substrate, and the second housing element 12 comprises a compression surface 132 arranged to oppose a flat bottom surface of the recess 131. When the aerosol generating device 1 is in the closed position as shown in FIGS. 1B and 1C, the compression surface 132 is arranged to oppose the bottom surface of the recess 131, and the portion 2 is compressed by the compression surface 132 towards the bottom surface of the recess 131. In this embodiment, the compression surface 132 is simply an extension of a surrounding flat surface of the second housing element 12, and is the part of the flat surface which is arranged to oppose the recess 131 in the closed position.

In some embodiments, compression alone may be sufficient to cause release of the aerosol from the substrate. However, in many embodiments, a heating element 14 is arranged to supply heat to the aerosol generation chamber 13 in order to heat the aerosol generating substrate and generate the aerosol. In such embodiments, the application of pressure increases the yield of aerosol from the aerosol generating substrate compared to heating alone. In the embodiment of FIGS. 1A to 1C, the heating element is arranged to supply heat through the bottom surface of the recess 131. The heating element 14 may, for example, comprise a resistive track that is powered by electricity.

In further alternative embodiments, heating may be supplied without the use of a heating element 14 in the device 1. For example, the portion 2 of aerosol generating substrate may also comprise a pressure-activated heat generating element such as a capsule of ingredients for an exothermic reaction.

The first housing element 11 may be formed from a thermally conductive material, such as a metal (e.g. aluminium), in order to allow heat transfer from the heating element 14 to the aerosol generating chamber 13. However, the spacing between the heating element 14 and the aerosol generating chamber 13 is preferably minimized, and the first and second housing elements 11, 12 preferably comprise a heat-resistant material such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polyamide (PA) in order to prevent thermal deformation or melting. The heat-resistant material may be a super engineering plastic such as polyimide (PI), polyphenylenesulfide (PPS) or polyether ether ketone (PEEK).

The device 1 also comprises an air flow channel 15 through the aerosol generation chamber 13, which is provided in order to extract the generated aerosol from the aerosol generation chamber 13. In the embodiment of FIGS. 1A to 1C, the air flow channel 15 comprises an inlet 151 connected between the exterior of the device 1 and one end of the aerosol generation chamber 13, and an outlet 152 connected between the exterior of the device 1 and another end of the aerosol generation chamber 13. The exterior of the device 1 around the outlet 152 is configured as a mouthpiece so that a user can inhale air and aerosol through the device 1. Alternatively, air may be artificially pumped through the air flow channel 15, for example using a fan.

In the embodiment shown in FIGS. 1A to 1C, the first and second housing members 11 and 12 are connected by one or more fasteners 16, which are hinges in this case, along a pivot line that is approximately aligned with a length direction between the inlet 151 and the outlet 152. By rotating on the hinges 16, the first and second housing elements 11, 12 move between an open position (shown in FIG. 1A) and a closed position (shown in FIGS. 1B and 1C). In the open position, the recess 131 is exposed, and the portion 2 of aerosol generating substrate can be added or removed, and the device can be cleaned. In the closed position, the aerosol generation chamber is completed and the aerosol can be generated. In other embodiments, the first and second housing members 11 and 12 may be fully separated in the open position, and may be connected together in the closed position by, for example, one or more releasable fasteners such as magnets or snap-fit connectors.

FIGS. 2A and 2B are schematic perspective illustrations of alternative portions of aerosol generating substrate.

In FIG. 2A, the portion 21 is a simple cuboid having length L, width W and depth D. In a typical example, the substrate is typically 18×12×1.2 mm, with each of L, W and D being selected within a range of +/−40%, for example.

The substrate may for example comprise nicotine or tobacco and an aerosol former. Tobacco may take the form of various materials such as shredded tobacco, granulated tobacco, tobacco leaf and/or reconstituted tobacco. Suitable aerosol formers include: a polyol such as sorbitol, glycerol, and glycols like propylene glycol or triethylene glycol; a non-polyol such as monohydric alcohols, acids such as lactic acid, glycerol derivatives, esters such as triacetin, triethylene glycol diacetate, triethyl citrate, glycerin or vegetable glycerin. In some embodiments, the aerosol generating agent may be glycerol, propylene glycol, or a mixture of glycerol and propylene glycol. The substrate may also comprise at least one of a gelling agent, a binding agent, a stabilizing agent, and a humectant.

The substrate is porous such that air can flow through the substrate and collect aerosol as it does so. The substrate may for example be a foam, or packed strands or fibres. The substrate may be formed through an extrusion and/or rolling process into a stable shape.

The portion of aerosol generating substrate is designed to be thicker (larger depth D) than the distance between the compression surface 132 and the bottom surface of the recess 131 when the device 1 is in the closed position. This means that the portion 2 must be compressed in order to reach the closed position with a portion 2 of aerosol generating substrate in the device 1.

As shown in FIG. 2B, in addition to being porous, the portion 22 of aerosol generating substrate may be shaped to provide one or more air flow channels. These can be aligned with the air flow channel 15 of the aerosol generating device 1 in order to increase air flow through the aerosol generation chamber 13.

In each of FIGS. 2A and 2B, the portion 2 has a bare external surface in which the aerosol generating substrate is exposed. Alternatively, the portion 2 may comprise an air permeable wrapper covering at least part of a surface of the aerosol generating substrate. The wrapper may, for example, comprise paper and/or non-woven fabric.

FIGS. 3A and 3B are schematic illustrations of compression of the aerosol generating substrate.

As shown in FIG. 3A, while the recess 131 may be a cuboid recess of length L, width W and configured to receive a cuboid portion 21 with the same length L, width W, a depth d of the recess 131 is however smaller than a natural depth D of the portion of aerosol generating substrate 2. As a result, when the device is in the closed position shown in FIG. 3B, it may be estimated that the aerosol generating substrate is compressed by a factor of d divided by D.

The inventors have found that compression of a substrate may result in improved heat transfer to the entire substrate, due to reduced amounts of air gaps therein, thus contributing to a shorter heat-up time to a suitable operating temperature, and a uniform amount of aerosol generation and an associated flavor throughout when the aerosol is inhaled.

Too weak compression i.e. too large ratio may not cause the anticipated results, and too strong compression i.e. too small ratio may cause an adverse effect due to reduced air-permeability through the substrate, such as an increased resistance to draw through a mouthpiece, and a reduced amount of aerosol delivery to a user.

FIGS. 4A to 4E are schematic cross-sections of different aerosol generating devices having alternative or optional features.

FIG. 4A illustrates an alternative aerosol generating device 1 in the open position. In this example, the compression surface 132 (1321, 1322) is not simply a part of a flat surface of the second housing element 12, but is raised or recessed relative to the surrounding surface.

FIG. 4B illustrates the recessed case, in which the consumable 2 partly engages with the recessed compression surface 1321. The thickness of the first and second housing elements 11, 12 is partly dictated by a required strength to reduce the chance of the elements breaking in use. Using a part of the second housing element 12 as space for the portion 2 of aerosol generating substrate uses the minimum volume of the device 1 (as dictated by strength requirements) more efficiently and increases the amount of aerosol which can be generated from the device 1.

Additionally, and independently from the specific compression surface 1321, the example of FIG. 4B illustrates how the heating element 14 may alternatively be located in the second housing element 12 to supply heat to the aerosol generation chamber through the compression surface 132.

FIG. 4C illustrates the case where the compression surface 1322 is raised relative to the surrounding surface of the second housing element 12. A raised compression surface 1322 allows a minimum depth of the recess 131 to be provided even for small portions 2 of the aerosol generating substrate.

Additionally, and independently from the specific compression surface 1322, the example of FIG. 4C illustrates how multiple heating elements 141, 142 may be arranged generally in the first and/or second housing elements 11, 12.

Furthermore, the example of FIG. 4C illustrates an insulating member 17 in the first housing element 11. The insulating member 17 comprises a material with lower thermal conductivity than the first housing element 11, such as an aerogel, inorganic fibers, or a foamed resin. Alternatively, the insulating member 17 may comprise a vacuum insulator. The insulating member 17 is arranged to partially enclose the aerosol generating chamber 13 and the heating element 14 in order to improve heating efficiency. For example, the insulating member 17 may be arranged to extend along one or more sides of a heating element 14 that are not facing the aerosol generating chamber 13 or one or more sides of the aerosol generating chamber 13. An insulating member 17 is similarly provided in the second housing element 12 to further insulate the aerosol generating chamber 13. In one example, the housing elements 11, 12 may be formed from a material which is not specialised for insulation, such as a metal, for example aluminium. At the same time, the insulating member 17 is formed from a substantially more insulating material such as polyimide (PI), polyphenylenesulfide (PPS) or polyetheretherketone (PEEK).

FIGS. 4D and 4E illustrate an alternative configuration of the compression surface in which a plurality of protrusions 1323 (or alternatively recesses) are arranged to oppose the recess 131 in the closed position. By providing multiple protrusions 1323 spaced apart from each other, the pressure applied to the portion 2 of aerosol generating substrate varies through the substrate, and air flow is higher in between protrusions. As a result, areas of higher aerosol generation (where pressure is applied by a protrusion 1323) are adjacent to areas of higher air flow, increasing the amount of aerosol which is extracted by drawing air through the aerosol generating substrate.

FIGS. 5A to 5D are schematic cross-sections of further different aerosol generating devices having alternative or optional features.

In FIGS. 5A and 5B, the inlet 151 and outlet 152 are rearranged as surface groove features of an air flow channel in the second housing element 12 extending through the compression surface 1324.

On the other hand, in FIGS. 5C and 5D, the air flow channel 15 is embedded within the second housing element 12 and, in the closed position, connects to the aerosol generation chamber 13 via one or more openings 153 in the compression surface 1325.

The alternative configurations of FIG. 5 have the advantage that air flow through the air flow channel 15 is not directly impeded by the portion 2 of aerosol generating substrate, and the aerosol is added to the air flow by evaporation, meaning that the pressure difference for drawing air through the device 1 is fixed and the strength of aerosol drawn from the device can be controlled according to the rate of drawing air through the device.

Additionally, the configuration of FIGS. 5A and 5B has the advantage that it is easier to clean a groove than an embedded channel.

As an additional variation, the air flow channel 15 may be provided partly in features of the first housing element 11 and partly in features of the second housing element 12. For example, each housing element may have a surface groove which, in the closed position, provides a part of the air flow channel 15.

FIGS. 6A to 6D are schematic cross-sections of different aerosol generating devices having further alternative or optional features. In particular, FIGS. 6A to 6D show variations on the housing elements 11, 12 and the fastener 16 of FIG. 1 .

In FIG. 6A, the first housing element 11 comprises a main portion 111 and a mouthpiece portion 112. The main portion 111 operates similarly to the example of FIG. 1 , and opposes the second housing element 12 in the closed position in order to form the aerosol generating chamber 13. However, in this example, the second housing element 12 does not extend as far as the outlet 152 meaning that the mouthpiece portion 112 is fixed.

Similarly, in FIG. 6B, the first housing element 11 comprises a main portion 111 and an inlet portion 113, where the second housing element 12 opposes the main portion 111 to form the aerosol generating chamber 13.

By providing a fixed outlet portion 112 or inlet portion 113, the air flow through the device 1 can be more predictably defined, even if the first housing element 11 and second housing element 12 are not perfectly positioned in the closed position, making the device 1 easier to operate.

FIGS. 6C and 6D illustrate an alternative aerosol generating device 1 in which the fasteners 16 are aligned perpendicular to the length direction between the inlet 151 and the outlet 152. This configuration may be easier for a user to operate and move between open and closed positions with one hand, leaving the other hand free for handling the portion 2 of aerosol generating substrate.

FIG. 7 is a perspective view of a first specific example of an aerosol generating device in the open position.

In this example, each of the first and second housing elements 11, 12 comprises an inner portion 111, 121 and an outer portion 114, 122. The outer portions 114, 122 provide an outer casing which is configured to be handheld. For example, the outer portions 114, 122 may comprise a rigid metal casing supporting weaker inner portions 111, 121. Additionally or alternatively, the outer portions 114, 122 may have lower thermal conductivity than the inner portions, in order to protect a user's hand, for example by providing an elastomer grip on an outer surface of the device.

Additionally, in the first specific example, the air flow channel 15 comprises a plurality of distinct inlets 1511 (two in this case) in one end of the outer portion 122 of the second housing element 12, to provide the inlet 151. Air then flows into two channels extending in parallel, the channels being formed as grooves on a surface of the inner portion 121 of the second housing element 12 connected between the inlet and the outlet. The grooves are surrounded by and separated by portions of the compression surface 132, with a similar effect to the example of FIG. 4D of providing regions of improved aerosol generation adjacent to regions of improved airflow in the portion 2 of aerosol generating substrate.

The grooves provide a channel of varying width between the inlets and the outlet, with small inlets and a comparatively large outlet. When air is drawn through the device 1 in the closed position, this configuration creates a pressure gradient in the air flow channel 15 and reduces the air pressure adjacent to the portion 2 of aerosol generating substrate, further increasing aerosol generation.

Additionally, in the first specific example, the heating element 14 (not shown in FIG. 7 but configured similarly to FIGS. 1B and 1C adjacent to the flat bottom surface of the recess 131) is driven by an external power source connected by electrical wire 18. The device 1 can be manufactured for use with an external power source, by cutting or moulding space for the electrical wire 18 in the inner portion 111 of the first housing element 11, and then providing a glue fill section 181 to separate the air flow channel 15 from the electrical wire 18. Alternatively section 181 could be an additional solid component that is fitted in place, such as a snap-fit or press-fit component. In some embodiments, the electrical wire 18 connecting to an external power source can be replaced with an internal power source. With an internal power source, the aerosol generating device can be provided as a portable handheld device.

Furthermore, in the first specific example, the device 1 comprises several closing means 191, 192 and 193 for improving the closure of the device 1 in the closed position and thereby making the device 1 easier to operate with good aerosol generation.

Firstly, the first and second housing elements 11, 12 are held in place in the closed position using one or more releasable fasteners (e.g. pairs of opposing magnets 191) opposed to the hinge 16. Providing releasable fasteners means that the device 1 need not be held in the closed position by hand throughout aerosol generation, making the device easier to use.

Secondly, tab surfaces 192 are provided which can be manually operated by a user's hand to open and close the device 1 between the open and closed positions. Providing the tab surfaces 192 means that the strength of the releasable fasteners can be increased without making it difficult for a user to move the device 1 from the closed position to the open position.

Thirdly, a gasket 193 is provided which, in the closed position, improves sealing of the air flow channel 15 between the inlet(s) and the outlet. The gasket may, for example, be formed from an elastomer such as rubber.

The first specific example of device 1 may suitably be used with a portion 2 of aerosol generating substrate that has a thickness D that gives a compression ratio d/D of between 0.6 and 0.9, more preferably between 0.7 and 0.8, wherein d is the depth of the recess 131.

FIG. 8 is a perspective view of the first specific example in the closed position (where the electrical wire 18 is not shown for simplicity).

As shown in FIG. 8 , the device 1 has a mouthpiece portion 112 similar to FIG. 6A surrounding the outlet 152. As further shown in FIG. 8 , an exterior surface of the second housing portion 12 is configured to align with an exterior surface of the mouthpiece portion 112 in the closed position, to provide a smooth exterior shape. FIG. 8 also illustrates that the tab surfaces 192 in the first specific example are configured to align in the closed position such that they can be easily pinched by hand in order to open the device 1.

Aerosol generating substrate includes tobacco, for example in dried or cured form, in some cases with additional ingredients for flavouring or producing a smoother or otherwise more pleasurable experience. In some examples, the substrate such as tobacco may be treated with a vaporising agent. The vaporising agent may improve the generation of vapour from the substrate. The vaporising agent may include, for example, a polyol such as glycerol, or a glycol such as propylene glycol. In some cases, the substrate may contain no tobacco, or even no nicotine, but instead may contain naturally or artificially derived ingredients for flavouring, volatilisation, improving smoothness, and/or providing other pleasurable effects. The substrate may be provided as a solid or paste type material in shredded, pelletised, powdered, granulated, strip or sheet form, optionally a combination of these. Additionally, the aerosol substrate may comprise a liquid or gel.

The aerosol generating device 1 could in some embodiments be referred to as a “heated tobacco device”, a “heat-not-burn tobacco device”, a “device for vaporising tobacco products”, and the like, with this being interpreted as a device suitable for achieving these effects. The features disclosed herein are equally applicable to devices which are designed to vaporise any aerosol substrate.

The aerosol generating device 1 may be arranged to receive the portion 2 of aerosol generating substrate in a pre-packaged substrate carrier. Filters, vapour collection regions, cooling regions, and other structure may also be included in some designs or the aerosol generating device 1.

As used herein, the term “fluid” shall be construed as generically describing non-solid materials of the type that are capable of flowing, including, but not limited to, liquids, pastes, gels, powders and the like. “Fluidized materials” shall be construed accordingly as materials which are inherently, or have been modified to behave as, fluids. Fluidization may include, but is not limited to, powdering, dissolving in a solvent, gelling, thickening, thinning and the like.

As used herein, the term “volatile” means a substance capable of readily changing from the solid or liquid state to the gaseous state. As a non-limiting example, a volatile substance may be one which has a boiling or sublimation temperature close to room temperature at ambient pressure. Accordingly “volatilize” or “volatilise” shall be construed as meaning to render (a material) volatile and/or to cause to evaporate or disperse in vapour.

As used herein, the term “vapour” (or “vapor”) means: (i) the form into which liquids are naturally converted by the action of a sufficient degree of heat; or (ii) particles of liquid/moisture that are suspended in the atmosphere and visible as clouds of steam/smoke; or (iii) a fluid that fills a space like a gas but, being below its critical temperature, can be liquefied by pressure alone.

Consistently with this definition the term “vaporise” (or “vaporize”) means: (i) to change, or cause the change into vapour; and (ii) where the particles change physical state (i.e. from liquid or solid into the gaseous state).

As used herein, the term “atomise” (or “atomize”) shall mean: (i) to turn (a substance, especially a liquid) into very small particles or droplets; and (ii) where the particles remain in the same physical state (liquid or solid) as they were prior to atomization.

As used herein, the term “aerosol” shall mean a system of particles dispersed in the air or in a gas, such as mist, fog, or smoke. Accordingly the term “aerosolise” (or “aerosolize”) means to make into an aerosol and/or to disperse as an aerosol. Note that the meaning of aerosol/aerosolise is consistent with each of volatilise, atomise and vaporise as defined above. For the avoidance of doubt, aerosol is used to consistently describe mists or droplets comprising atomised, volatilised or vaporised particles. Aerosol also includes mists or droplets comprising any combination of atomised, volatilised or vaporised particles. 

1. A system comprising an aerosol generating device and a portion of aerosol generating substrate, the aerosol generating device comprising first and second housing elements configured to move between an open position and a closed position, wherein, in the closed position, the first and second housing elements together define an aerosol generation chamber configured to enclose the portion of aerosol generating substrate, and further define an air flow channel comprising an inlet, an outlet and the aerosol generation chamber, the first housing element comprising a recess for receiving the portion of aerosol generating substrate, wherein the recess comprises a flat bottom surface, and the second housing element comprising a compression surface for compressing the portion of aerosol generating substrate towards the bottom surface of the recess, the compression surface and the bottom surface being opposing surfaces of the aerosol generation chamber, wherein the portion of aerosol generating substrate is cuboid and a thickness D of the portion before use in the aerosol generating device is greater than a distance d between the compression surface and the bottom surface of the recess when the first and second housing elements are in the closed position.
 2. The system according to claim 1, wherein a compression ratio d/D between the thickness D of the portion before use and the distance d between the compression surface and the bottom surface of the recess is between 0.6 and 0.9.
 3. The system according to claim 1, wherein the first and second housing elements are connected by a hinge.
 4. The system according to claim 1, the aerosol generating device further comprising a fastener for holding the first and second housing elements in the closed position.
 5. The system according to claim 1, the aerosol generating device further comprising a gasket configured to, in the closed position, seal the air flow channel between the inlet and the outlet.
 6. The system according to claim 1, the aerosol generating device further comprising a heating element arranged to supply heat to the aerosol generation chamber through the bottom surface or the compression surface.
 7. The system according to claim 1, wherein the first housing element and/or the second housing element comprises an insulating member at least partly enclosing the aerosol generation chamber.
 8. The system according to claim 1, wherein the second housing element additionally comprises second air flow channel configured to connect to the aerosol generation chamber in the closed position, and to provide the inlet and the outlet.
 9. The system according to claim 8, wherein the second air flow channel comprises a groove in a surface of the second housing element.
 10. The system according to claim 9, wherein the second air flow channel comprises a groove in the compression surface.
 11. The system according to claim 10, wherein the second air flow channel comprises a plurality of grooves in the compression surface connected between the inlet and the outlet.
 12. The system according to claim 11, wherein the inlet comprises a plurality of distinct inlets connected to the plurality of grooves.
 13. The system according to claim 11, wherein the plurality of grooves are arranged in parallel between the inlet and the outlet.
 14. The system according to claim 11, wherein a plurality of sections of the compression surface are separated by the plurality of grooves of the second air flow channel, and each of the plurality of sections of the compression surface is configured to compress the portion of aerosol generating substrate towards the bottom surface of the recess.
 15. The system according to claim 1, further comprising an electrical power source, wherein the aerosol generating device is a portable handheld device.
 16. The system according to claim 1, wherein a compression ratio d/D between the thickness D of the portion before use and the distance d between the compression surface and the bottom surface of the recess is between 0.7 and 0.8. 